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Cheerlights Desktop Christmas Tree 


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Cheerlights Desktop Christmas 


Written By: Jeff 


This tree is nothing more than 10 RGB (red/green/blue) LEDs connected in parallel to an 
Arduino with an Ethernet Shield running a modified version of the cheerlights sketch. 

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Cheerlights Desktop Christmas Tree 

Step 1 — Cheerlights Desktop Christmas Tree 

While I was waiting for my 
shipment of RGB LEDs to arrive, I 
went ahead and did a test run with 
the Arduino and a single LED. 
Then, wanting to make sure I didn't 
overload the Arduino's outputs, I 
whipped up a little board with NPN 
transistors to take the load off. 
Turns out I probably didn't need it, 
but left it in anyway. Astute readers 
will notice that I have 3 extra 
resistors. Turns out that the LED 
with which I did my original testing 
(acquired at Radio Shack) needed 
different resistor values than the 
twenty I got from Sparkfun. 

Good instructions for connecting an 
RGB LED to an Arduino can be 
found at 

I downloaded the code from .. 
and replaced the GE Color Effects 
code bits with code from the 
aforementioned Instructables 
article to drive RGB LEDs. I had to 
invert the color values (replace 255 
with and vice versa) to reflect the 

My final code can be found at 

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Cheerlights Desktop Christmas Tree 

Step 2 

After testing the LEDs on the 
breadboard, I soldered 'em up into 
a tree. I thought this would be the 
hardest part, but it wasn't so tricky. 

Step 3 

m u M^ m u l ■& ^kJ Wf § 1 


With the tree mounted to the box (a 
bamboo kitchen utensil holder), I 
connected the Arduino setup. 

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Cheerlights Desktop Christmas Tree 

Step 4 

Dialing in each color is what 
actually took the longest, staring 
into bright lights and trying to 
conjure a perfect white. 

This document was last generated on 2012-11-02 07:40:58 PM. 

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